Dental casting post



June 2, 1931.' D. E. vANs DENTAL CASTING POST Fileifmay 7, 1929 PatentedJune 2, 1931 UNITED STATES HPixrnlxli" oFFic/Ez DAVID E. EvANs, orcoLUMBUs, 01110, Assreivon 'ro THE connMBUsnEN'rAL MAN'U- i rAo'runINeCOMPANY, or ooLUMBUs, onro, A coRPoRA'rIoN DEN'L'AL CASTING rosrApplication filed May 7, 1929. SeraIN'o. 361,022.

I am aware that casting posts have been used heretofore in dentistry, inassociation With artificial teeth and especially interchangeableartificial teeth. Their purpose and function are well understood bythose skilled in the art.

The casting post usually is composed of a precious metal alloy. The postis so shaped and formed that only a portion engages, or

` coacts, with an artificial tooth. The remaining portion of the castingpost proj ects above the artificial tooth so that Wax may be formedabout the post to make a base, or |hacking member. The Wax andcastingpost are next K5 removed silpnultaneouslyi fro-m the tooth.

. Then through the well-known dental casting technic vthe Wax isreplaced with metal, the latter usually composed o-f a stable preciousmetal alloy.

Casting posts have been madeand sold by dental manufacturers todentists, to be used in the way set forth and for the purpose of aidingin artificially restoring lost natural teeth. This method ofrestorationusually applies to what is oommonly called bridge- Work. i

What has been recited is understood and practiced generally in the art.

One object of my invention is to so construct the casting post that ithas inherent retentve, or holding power when the Wax is formed about it.In the past many ofthe casting posts have separated from the wax duringthe construction of a dental bridge and have thus caused loss of bothlabor and time. This is p-a-rticularly a disadvantage to the dentist.

Another object of my invention is to so construct the casting post thatit has inher- 49 ent retentve, or holding power, when the metal is castagainst it. In the past it was not uncommon for the post to separatefrom the cast metal, the former sometimes pulling away bodily. Thisfrequently occurred after the bridge was in service in the patientsmouth. In such cases the cast gold did not attach itself strongly to thepost during the process of casting. .In fact the degree of strengthbetween the two, in repeated trials, 59 is seldom constant and poorunions are apt to occur at any time. Such fa'ilures are serious mishaps,both to the patient and dentist. Either, or both parties suffer muchinconvenience and loss of time.

Another object of my invention i-s to so construct the casting post thatit will beunnecessary to use hi'h fusing casting metal, Dr over heatlower fusing casting metal in an efiort to procure a rigid union betweenthe post and casting metal. -In the past it has been common to over heat'the lower fusing casting metals in an effort Vto getl greater strengthof union with the post by sweating or alloying. This procedure hasa'tendenicy to burn outsome of the lower fusing metals in the castingalloy, which may cause the alloy to 'changemateriallyi in its physicalproperties. Such physical property changes sometimes leads to failureduring'the casting process, or may effect the tensile strengthof o afinished piece' of work. Further, the overheating. of the casting alloyoften seems to' have -a deleterious effect upon the metal of thelcasting post. Breakage of the. post itself, is not an uncommon failurein -such in- 'stances The exact'cause of the breakage of the post itselfis not known to me, yet it has been construed that mixing differentalloys of different characteristics may upset the 'physical propertiesofboth metals. In this 'instance the casting post'is an alloy possessingdifferent 4characteristics than the casting alloy. Further, it has beenconstrued that the 'post breaks under these conditions because i thearrangement of the molecules of the metal have been disturbed andcry-stalization has taken place. Regardless of the exact cause,breakageof the post does occur at times when this process of high heatcasting is employed. i What Vhas been said above applies in spirit whenVa 'casting alloy of high fusing range is ,employed vin association witha post whose fusing range is more 'or less lower.

When my casting post is employed it is unnecessary to over heat thecasting alloy or use a higher fusing casting alloy. Through the inherentretentve construction of my post, the casting alloy is retained in amechanical way in addition to any `surface sweating union that may takeplace during the casting process.

Another object of my invention is to so construct the casting post thatit satisfies the requirements for practical production in manufacture. i

i In the drawingsr' J i,

Figure 1 is a side elevation of a casting post embodying my invention.

post.

Figure 3 is an end elevation of the same,

The reference numeral 1 designates' the post, 2 the web which is oflessdiameter than the post, and 3 the retaining member, all

formed integrally, preferably vby casting.

The retaining member, preferably, is 'wedge shape 1n one dnnenslon asshown in Figura 1,

the side edges 4 and 5 converging toward the web 2. In the edge 9 of theretaining member 3 I provide an arcuate recess or depression and form aswelled protruded, or bulbouslike extension 10, 11 on each side wall ofthe retention member 3 the top of which is in the plane ofthe bottom andside walls of the recess 8, said extensions 10, 11, functioning asadditional anchorage for the hacking metal cast on the post. LetV it beunderstood that by the termpost I mean the article as a whole.

In the manufacture of my casting post, I

may choose to construct it so that the post 1 may have one' or aplur'ality of'notches 1a as shown in Figure 1. The function oflthesenotchesis to serve as a mechanical retention for the post, When thelatter is assembled with the artificial tooth, the two being de-'tachably united by cement, or Vany other suitable material. i

It will readily be understood that the metal for the hacking cast to mycasting post finds 'a very firm anchorage in the wedge forma;

tion of the retention member andin the bulb ous formations 10 and 11.

What I claim is: p 1. vAs a new article of manufacture,`v a casting postfor the hacking for an artificial :tooth, comprising a post, a Web, anda reten tion member having a recess in its rear edge and protuberances.from two side. Walls thereof, all formed integrally.

V2. As a new article of manufacture, a casting post, for the backing,for an artificial too'th, comprising a post, a web, and' a retentionmember, having a recess in its rear edge and protuberances on two sidewalls thereof along the bottom and side walls of the recess. Intestimony whereof I `aflix my signature.

' DAVID E. S.

Figure 2 is a rear elevation of. my casting

